Modeling optical contrast for thin organic films on the sea surface

A continuation of the work dedicated to the study of slicks and film formations on the sea surface is presented. A vector model for the calculation of reflected radiation by the wavy sea surface with respect to the contribution of upwelling radiation from under the sea surface (the second type of waters) is described briefly in [5]. This work contains an analysis of numerical calculations according to the developed procedure and the search for optimal conditions of slick detection. The best conditions for detecting slicks on the sea surface are reached when a P-polarization component of reflected radiation is recorded. In this case, the value of contrast between a slick and a clean surface is 30% higher on average than in recording a contrast without using a polarization filter and is 50% higher than in the case of recording a contrast with a filter oriented to the maximum transmission of S polarization component of reflected radiation. It is shown that, under clear sky conditions, the optimal condition for recording slicks on a sea surface is videotaping in the plane of solar vertical at viewing angles sliding towards the sea surface and when a polarization filter that identifies the Р polarization component of sea radiation is used. In contrast, under overcast sky conditions, it is best to perform observations in the plane that has a wind velocity vector.     

Modeling of the sea surface for daylight imagery studies

Plastic-coated paper is shown to possess reflectivity characteristics quite similar to those of the surface of water. This correspondence has been used with a conversion factor to model a sea surface by means of plastic-coated paper. Such a paper model is then suitably illuminated and photographed, yielding physically simulated daylight imagery of the sea surface under controlled conditions. A simple example of sinusoidal surface simulation is described     

On classification of sea surface oil films using TerraSAR-X satellite polarization data

The paper presents the results of applying a new polarization method proposed in [28] to identify the type of surface pollution and differentiate between mineral oil films (crude oil and its emulsion and petroleum products) and films of other origin in sea surface radar images. The method is based on calculation of the quantitative characteristics for the ratios of suppression or intensification of scattered radio signals of different physical nature, viz., caused by capillary ripples several centimeters long, or wave breaking. TerraSAR-X satellite coaxial-polarized (VV/HH) SAR images are used. The data for analysis have been collected in areas where spots and slicks of known origin regularly occur, such as oil spills and natural oil seeps in the Gulf of Mexico and the Caspian Sea, and biogenic films in the Caspian Sea. The results of analyzing radar images from the TerraSAR-X satellite with controlled experimental oil emulsion spills in the North Sea are used for comparison. Based on the analysis of ten TerraSAR-X radar polarization images with surface sensing angles greater than 30°, it is shown that this method makes it possible to distinguish between oil spills and slicks formed by natural oil seeps and biogenic films with an accuracy higher than 80% regardless of the observation area.     

渤海海面太阳辐照强度的观测分析与计算方法研究

对渤海海面(1998-09-24～10-07和1999-04-28～05-11)实测太阳辐射日总量同云量的关系和春、秋季的对比关系及其与插值计算出的晴日太阳辐射日总量的关系进行了分析,并同烟台(福山)测站的结果进行了对比分析.通过分析发现,渤海海面太阳辐射日总量春季远大于秋季,其无云条件下的太阳辐射日总量与插值计算出的晴日太阳辐射日总量的差异秋季大于春季.分析表明,海陆温差引起的海面大气垂直输送与水汽物的产生是造成这种差异的主要原因.采用经验公式对渤海海面太阳辐射日总量进行计算,计算结果与实测结果具有较好的一致性.结果表明所用经验公式及推算出的参数适合于春、秋季渤海海面太阳辐照度的计算.     

Comparison of sampling devices for the determination of polychlorinated biphenyls in the sea surface microlayer

Over 30 sea surface microlayer (SML) samples from two contrasting sites in the North Western Mediterranean -- Barcelona (Spain) and Banyuls-sur-Mer (France) -- were collected using three different sampling devices, namely, glass plate, metal screen (MS) and a surface slick sampler (SS), and compared with the corresponding underlying water (16 samples). The distributions of 41 polychlorinated biphenyl congeners (PCBs) were determined in the different phases: particulate (1.17-10.8 SigmaPCB ng L(-1)), truly dissolved (0.080-16.7 SigmaPCB ng L(-1)) and colloidal matter (1.17-43.0 SigmaPCB ng L(-1)), being the last two estimated from the analysis of the apparently dissolved phase. Concentrations of PCBs in the SML were higher than those in the underlying water (ULW), giving rise to enrichment factors (EF=[C](SML)/[C](ULW)) up to first-order of magnitude. The ANOVA statistical approach was used to assess differences of bulk data (e.g. dissolved organic carbon, DOC; particulate organic carbon, POC; suspended particulate matter, SPM) among sampling devices, whilst p-tailed t paired tests were used in order to compare the enrichments obtained for each sampling date. In this respect, no significantly different enrichment factors were found among sampling devices (p < 0.05), although the surface SS showed lower enrichments, probably due to the dilution of the SML with the ULW during sampling. The MS seemed to be the most suitable device for the determination of PCBs in the SML in terms of sampling efficiency under a variety of meteorological conditions.     

Field investigations of the drift of artificial thin films on the sea surface

The results of field investigations of the drift of surface films are presented. The experiments were performed at the southern coast of the Crimea in the area of an oceanographic platform. It is shown that the drift of a thin film is described well by a linear combination of the vectors of the coastal current and wind, and the coefficient of the current velocity is close to unity. The total velocity of wind and wave drifts is 0.013 of the wind velocity magnitude or 0.38 of the air friction velocity. Analysis of experimental data demonstrates an increase in the film spreading rate with increasing wind velocity.     

A new expression for the production rate of sea water droplets on the sea surface

A new set of empirical formulas for the production rate and the number concentration of sea-water droplets on the sea surface are proposed, synthesizing past observation data of sea-salt particles in the sea and water droplets in wind-wave tanks. A new levelz _c is introduced as the effective wind-sea surface where seawater droplets are produced. The new formulas are expressed in linear functions in logarithmic scales ofu*²/v _p , a parameter to describe overall conditions of airsea boundary processes, whereu _* is the friction velocity of air,v the kinematic viscosity of air and _p the peak angular frequency of wind-wave part of wave spectra. A model of coexistence of spray droplets and suspended particles near the sea surface is proposed. As for the independent parameter, a comparison between the uses ofu*²/v _p and ofu _* ³ which was the traditional way of parameterization excluding wave measure, shows that the advantage of usingu*²/v _p is statistically significant with a confidence limit 89% in F-test.     

基于热红外图像的海面油膜面积的测算方法

针对现有油膜检测技术难以准确测算油膜面积且检测精度受天气条件影响大的问题,本文提出了一种基于热红外图像的海面油膜面积测算方法。采用波段为 8耀14 滋m 的红外热像仪获取海面油膜的热红外图像,对采集的油膜图像进行预处 理 （灰度化、中值滤波和锐化）;基于图像灰度分布特征分割油膜区域 （感兴趣区域,ROI）,采用形态学操作对 ROI 进行填充、腐蚀与膨胀,并对 ROI 进行数学表征;通过像素面积法计算 ROI 实际物理面积。实验结果表明：在不同的外界天气环境下 （如海浪、海风、海雾、不同光照等环境）,该方法对不同黏度的石油样品在海面形成的油膜均有良好的检测精度, ROI 面积计算平均误差为 3.77%。     

具有A.K.Fung 海谱的粗糙海面电磁散射的微扰法研究

运用微扰法研究了平面电磁波入射随机粗糙面的电磁散射问题,得到了具有A.K.Fung海谱的粗糙海面散射截面的数学表达式,进一步得出了不同极化状态下散射系数的计算公式.通过数值计算得到了双站和单站两种情形下散射系数随散射角、风速、入射波频率变化的曲线,讨论了粗糙面高度起伏均方根、海水温度、风速、入射波频率对散射系数的影响,...     

Fatty-acid composition of dissolved and particulate matter in surface films

Lipids containing fatty acids, together with other surface-active substances, can form continuous films on the sea surface. Owing to the complex structures of fatty acids, they are suitable for use as tracers in investigations of the origin and fate of surface films.Surface films were sampled west of the island of Sylt from the 20th to 22nd of August, 1974. After filtration, the fatty-acid composition of the chloroform-soluble part was analyzed in the particulate and dissolved fractions, respectively. Thereby different types of surface films could be characterized, which varied in total quantity, as well as in the relative amounts of fatty acids in the filtrate and particulate matter.It is plausible that such fatty acids will accumulate at surfaces which are chemically stable, as e.g. the saturated fatty acids, which are more resistant to photolytic and chemical degradation than their unsaturated counterparts.The fatty-acid patterns changed as soon as the film contained a large amount of particulate lipids, which shows correlations to the dissolved surface-active substances. Thus, correlations between the fatty-acid pattern in the surface film and that of Prorocentrum micans could be determined.     

印度洋海表盐度预报的线性马尔可夫模型及其改进办法

海洋盐度在水循环、海洋环流、海洋生态系统、全球天气和气候变化等方面起着至关重要的作用。然而,受观测的限制,以往对海洋盐度的研究相对匮乏,对其进行预报的工作更为少见。本文采用线性马尔可夫模型对印度洋海表面盐度(sea surface salinity,SSS)开展初步的预报工作。根据混合层盐度收支方程,选择海表面高度(sea surface height,SSH)、海表面温度(sea surface temperature,SST)、SSS等物理量的异常值作为模型的组成部分,对印度洋SSS开展预报工作。结果表明,马尔可夫模型可提前9个月对印度洋SSS进行较好的预报。此外,南太平洋海表面温度异常(sea surface temperature anomaly,SSTA),海表面高度异常(sea surface height anomaly,SSHA)和印度洋偶极子(Indian Ocean dipole,IOD)系数等遥相关因素的加入可将线性马尔可夫预报对印度洋SSS的预报效果(相关系数)平均提高10%。利用改进的模型对印度洋SSS进行提前1～11个月的“实时”预测,得出预报的SSS时空变...     

On the parameterization of drag coefficient over sea surface

Six parameterization schemes of roughness or drag coefficient are evaluated on the basis of the data from six experiments. They present great consistency with measurement when friction velocity u*<0.5 m/s (approximately corresponding to 10 m wind speed U10 <12 m/s) and large deviation from measurement when u*≥0.5 m/s (approximately U10≥12 m/s). In order to improve the deviation, a new parameterization of drag coefficient is derived on the basis of the similarity theory, Charnock relationship and Toba 3/2 power law. Wave steepness and wind-sea Reynolds number are considered in the new parameterization. Then it is tested on the basis of the measurements and shows significant improvement when u*≥0.5 m/s. Its standard errors are much smaller than the ones of the other six parameterizations. However, the new parameterization still needs more tests especially for high winds.     

Experimental studies of thermal radiation intensity dependence on near-water wind speed for rough sea surface

The results of in situ measurements of the characteristics of intrinsic microwave radiation from the sea surface are presented. The studies were carried out on the oceanographic platform of the Experimental Department of Marine Hydrophysical Institute during the summer–fall periods for 3 years, which made it possible to accumulate a significant amount of information on the change in the radiation intensity of under different meteorological conditions. Attention is primarily focused on the construction of wind-radiation dependences and their steepness analysis based on the measurement data obtained by a radiometer-polarimeter with a central frequency of received radiation equal to 37.7 GHz. The results are compared with the previous experimental studies and the model estimates of this effect.     

Waves and diffusion on the sea surface

The frequency spectrum of surface elevations in the presence of wind waves is well known. On this basis, one can estimate the frequency spectrum of vertical velocities in sea-surface waves. Owing to liquid incompressibility, the spectrum of horizontal velocities should have the same frequency dependence. The use of the dispersion equation for waves on the surface of a heavy liquid allows one to obtain to the spatial spectrum of velocities. Therefore, one can estimate the spatial structure function of the velocity field. For short waves and large depths, the structure function increases as r ^1/2, where r is the distance between the points of observations. For long waves and shallow depths h, this increase is proportional to r. The coefficient of turbulent mixing K(r) of pollution spots of size r on the sea surface is now estimated as the product of the spot size and the rms difference of velocities. As a result, depending on r and h, the exponent in the r ⁿ dependence of K(r) may vary between 1.25 and 1.5. This outcome provides an explanation for a scatter in the values of the exponent n, a phenomenon that has been observed by many experimentalists.     

福鼎海域坛紫菜叶状体体表外生细菌的组成和数量分析

从采集自福鼎敏灶湾和硖门湾海域的健康坛紫菜（Porphyra haitanensis）叶状体体表分离、纯化到26株外生细菌．根据细菌菌落特征、菌体形态和16SrDNA基因序列分析相结合的方法进行鉴定,将其确认为6种不同的菌属,分别是假交替单胞菌属（Pseudoaheromonas）、Aquimarinas属、交替单胞菌属（Aheromonas）、黄杆菌属（Flavobacteriums）、弧菌属（Vibrio）和嗜琼胶菌属（Agarivorans）．2个海湾坛紫菜叶状体体表外生菌群数量稳定且差别不大,外生细菌菌属组成基本相同,个别菌属稍有差异,优势菌属为假交替单胞菌属和Aquimarinas属,常见菌属为交替单胞菌属和黄杆菌属,少见菌属为弧菌属．敏灶湾坛紫菜体表外生菌群数量为（5．7～6．5）×10^4cfu／g,外生细菌中各菌属所占比例为：假交替单胞菌属占38．5％,Aquimarinas属占52．8％,交替单胞菌属占13．9％,黄杆菌属占11．5％,弧菌属占3．3％．硖门湾坛紫菜体表外生菌群数量为（6．4～7．6）×10^4cfu／g,外生细菌中各菌属所占比例为：假交替单胞菌属占37．3％,Aquimarinas属占32．0％,交替单胞菌属占14．0％,黄杆菌属占12．7％,弧菌属占2．7％,嗜琼胶菌属占1．3％．优势和常见菌属菌株对健康坛紫菜叶状体进行感染,发现这些菌株对坛紫菜叶状体无致病力,叶状体生长无异常．这些可为坛紫菜微生物学研究提供基础资料．     

Empirical method of diurnal correction for estimating sea surface temperature at dawn and noon

An empirical method has been developed for estimation of sea surface temperature (SST) at dawn and noon in local time from microwave observations at other times of the day. By using solar radiation, microwave sea surface wind, and SSTs, root-mean-square differences were reduced to approximately 0.75 and 0.8 °C for dawn and noon, respectively. The pseudo SST variation and spatial patterns found in daily mean SST values by simple averaging of samples were damped down by use of diurnal correction. The satellite SST with the diurnal correction shows highly significant coherent variation with in-situ measurements.     

The input of organic material to the oceans: air—sea interactions and the organic chemical composition of the sea surface

In order to understand and quantify the way in which organic matter is transported from the atmosphere to the oceans it is important to know not only the various mechanisms by which the material is transferred between the two phases, but also the role of natural organic material at the air—sea interface in modifying such transport. In order to predict the latter it is necessary to have some knowledge of the organic chemistry and physico-chemical properties of material at the sea surface. Its organic chemistry is presently the subject of considerable controversy, although surface pressure measurements and force-area data for sea surface material, together with its very mixed chemical nature, strongly suggest that over most of the oceans it cannot form a coherent film.Transfer of organic material across the air—sea interface can be by either wet (liquid) or dry (gas and solid) deposition. The flux carried by each path can be characterised by the product of the rate of transfer of the substance concerned and its concentration in the transporting phase. Any modifying effect of material at the sea surface will vary depending on the mode of transfer, as well as the properties of the interfacial material. Application of these ideas is illustrated by calculation of atmosphere—ocean fluxes for total organic carbon, CCI₄, CCI₃F, PCBs and DDT.     

基于微波遥感技术海面盐度反演方法

海面盐度(sea surface salinity,SSS)是研究海洋变化及其气候效应重要的物理量,对海洋生态环境、海洋可持续发展至关重要.为了提高海面盐度反演精度,本文通过对SMAP卫星L波段微波辐射计测量的亮温数据进行海面盐度反演研究,考虑风、浪等影响海面粗糙度的环境因子对Klein-Shift模型(简称K-S模型...